Machine gun feed control



May 22, 1945. J, Q T TE 2,376,736

MACHINE GUN FEED CONTROL I Filed June 10, 1941 2 Sheets-Sheet l INVENTOR JOHN 6. 77907702 r ATT NEYS y 1945- J. C.TROTTER 333,376,736

MACHINE GUN FEED CONTROL Filed June 10, 1941 2 Sheets-Sheet 2 INVENTOR Jaw/v c. fearme Patented May 22, 1945 UNITED. "STATES PATENT Ql-FI CE John-G. r-Trotter, Williamsville, N. Y. assignor to .Bell Aircraft Corporation, Bufialo, N...Y.

*AppIication June' 10, 1941; Serial No. 397-;421

. 3 Claims.

This invention relates to rapid fire guns, and more particularly to aerial machine guns of the cartridge belt fed type, 1 and to improved means for feeding ammunition thereto. More specifically,'the invention provides an improved mechanism for controlling the issuance of 'acartridge belt from a magazine located' above the associated gun, as in the case 'of a gun mounted within a tunnel-' or blister located in the belly of an airplane'fuselage, 'or thelike, in'which caset'he ammunition magazine therefor its most advantageously located within'the mainfuselage section above the gun position.

'In connection witha flexibly mountedgun the cartridge belt' leading thereinto must be unconlined in the region adjacent the'gun so as to allow the belt to "flex and twist as the gun is trained in azirnuth'and elevation. Consequently it is impracticable in such case to enclose" the cartridge belt between the magazine and the cartridge feedwayof the gun by'means of a close fitting conduit to prevent siphoning ofthe cartridge belt out of the magazine at a "rate in excess of the cartridge feeding requirements ofthe gun. It'will'be understood that if such siphoning is permitted the contents of the ammunition magazine will simply'pour uncontrolled out into the gunners compartment,v thus interfering with the normal functioning of the combat unit. Previous efiorts to solvethis problem-have resulted in attempted use of friction devicesin association with the magazine outlet opening, but vertical acceleration "forces developed during combatmaneuvers of an airplane are at certain times so high that such friction devices areentirely inoperative under such conditions for the purpose intended.

One of the objects of the present inventionis to provide a positivelyacting means for controlling movement of acartridge belt out ofitscontaining magazine so as to-permit free movement thereof toward the associated gun in full response to feeding requirementsof thegun, but toprohibit .overrunning tendencies of the cartridgebelt relative to the requirements of .the

feed pawl mechanism of the gun under all conditions of maneuvering of the'mounting airplane. Another object of the invention, is to provide-a device of the character described which is adapted to function with equal :facility in conjunction with either fixed or flexibly mounted-guns. Other objects and advantages of the invention will appearin the specification hereinafter.

.In the drawings:

tion of a machine gun-teed mechanism ofthe invention;

Fig. '2 is anenlarged fragmentary view ofa detail'of a control means thereof; and

Fig. 3 is a view"corresponding generally to-Fig. l o'f another form of the invention.

The drawings ill-ustratethe invention in-conjunction with a machine gun-designated-generally'at ['0 (Fig. 1) which'is 'shown *as' being "arranged for flexible mounting upon a trunnion bracket- 2. A belt of linker cartridges designated at M is shown'arranged-in operative connection with the cartridge fee'dwa-y IS of the *gun and the associatedgunieed pawl mechanism (not shown) The cartridge belt magazine is indicated at Wand the usual'lap folded arrangement of the cartridge-belt withinthemagazine is indi Gated diagrammatically at H. Thus, Fig. 1'illustrates a 'typical machine gun and magazine arrangement wherein the g-un is located below the magazine; as within a blister 'or' tunnel portion of-an' airplane extending'below the'ma'in fuselage section in which the-magazine is housed.

A cartridge'belt outlet conduit-[8' is-arrangd in open communication at one of its ends with'the outlet opening of the magazine 'IB, and is so shaped as to accommodatethe cartridge belt [4 in freely slidable relation therein and to be adapted to guide the cartridge belt intogeared engagement 'with'a'star wheel 20 which is rotatablycarried .upon'a bracket 2| (Fig. 2) extendingv from theconduit f8,'by'means'of a shaft 22. rThe'star wheel- Zllis so mounted relative'to the outlet'end portion of the conduit *l 8 "as to engage thereatin geared relation with the partridgebelt I 4; and a lip portion is provided-to extend from the conduit I8 to insure positive engagement between thecartridgebelt' l4 and the star wheel 20 as the cartridge'belt'mov'es through the conduit l8.-toward theguntll. 'A'pa'ir 'of guide rolls 25 (Fig 1) are disposedat opposite sides of the cartridge belt l4 ata'position'spaced below the star"whee1 20, and anidler "roller' 26 is mounted upon'tone end of'a bell crank '28 so asto be disposed in rolling contact against the cartridge belt l4 betweenthe positions of-the star wheel '20" and the guiderolls 25. Thebe'Il crank 28 is pivotally mounted asatZS-to-a suitable fixed support and; is connected at its'opposite end to a spring '30 which-isunder tension so -that the idler '26 tends atall times-t0 move the cartridge belt l4 out of line with' the star'wheel Ell-.andatherolls 2-5; as illustrated in Fig. 1. The star wheel 20 is :arrangedto" be "normall-y locke'd Fig. 1 isla. fragmentarydiagrammaticl-eleva- 55 i-n'inoperative p i i n'bym ns'fl a in p ri 32 (Fig. 2) which is normally biased into looking position by a compression spring 33. The pin 32 is connected to the armature of a solenoid 34 carried by a bracket 35 suspended from the corn duit I3 and is keyed to the shaft 22 for engagement with the locking pin 32 whenever the latter is spring-pressed outwardly,

It will be understood that, by reason of the organization of the operative parts of the mechanism as illustrated and described, upon commencement of a gun firing operation the gun feed pawl mechanism of the gun ill will provide a drag force upon the lower end of the cartridge belt M in connection with drawing of the cartridge belt into the cartridge feedway l5 of the gun.

Because of the initial locked condition of the star wheel this drag of the gun feed mechanism will cause the cartridge belt id to tend to straighten out between the positions of the guide rolls and the star wheel 26. Thus, the cartridge belt will act against the idler roller 26 in such manner as to cause the bell crank 28 to pivot against the action of the spring 30 and to press against the extending finger ii) of a switch 42 so as to close an electrical circuit including conductors M, and 46 and the winding of the solenoid 34. Thus, the solenoid will be energized to cause the locking pin 32 to be retracted out of the locking engagement with the star wheel shaft against the action of the spring 33 until such time as the cartridge belt I4 may be relaxed between the positions of the star wheel 20 and the guide rolls 25 so as to allow the spring 30 to pivot the bell crank 28 back to circuit-open position. Upon cessation of the gun firing operation, or stoppage of the gun for any reason whatsoever, the drag of the gun feed pawl mechanism upon the cartridge belt ceases and the pull against the idler roller 26 is relaxed so that the spring 30 restores the bell crank to the position in Fig. 1, whereupon the circuit of the solenoid 34 is opened and the locking pin 32 is allowed to emerge again into star wheel locking position. Thus, the movement of the cartridge belt I i through the conduit i8 is again blocked until such time as the gun firing operation is recommenced, whereupon the process described hereinabove will be repeated.

If preferred, a guide roller (Fig. 1) may be arranged to be rotatably carried by a suitable bracket extending from the gun Hi so as to properly guide the cartridge belt M into the gun feedway l5 under all conditions of gun training adjustment; the twisting of the cartridge belt 14 being thus arranged to take place between the rollers 25 and 50.

Thus, it will be understood that the invention contemplates provision of a cartridge belt movement controlling member arranged adjacent the outlet of the ammunition magazine for normally blocking emergence of the cartridge belt therefrom. However, upon commencement of a gun firing operation, the drag imposed upon the cartridge belt by the operation of the feed pawl mechanism of the gun per se automatically operates to cause the controlling member to become inoperative and to allow the cartridge belt to move downwardly through the guide means toward the cartridge feedway of the gun in continuously feeding manner. Immediately upon stoppage of the gun feed pawl mechanism or overrunning movement of the cartridge belt relative to the requirements of the gun feedpawl mechanism, the slackening of the belt 14 between the positions of the gun and the magazine outlet automatically operates to cause the movement controlling member to return to cartridge belt blocking position, and siphoning of the belt from the magazine is prevented.

Fig. 3 illustrates another form of the control mechanism of the invention wherein a star wheel is arranged adjacent the outlet end portion of the magazine outlet conduit l8, as in the manner of the mounting of the star wheel 20 of the form of Figs. 1 and 2. A locking pin 56 is slidably mounted with a tubular casing 58 carried by a bracket 59 extending from the conduit 18, so as to be axially slidable into and out of l0cking engagement with the star wheel 55. The pin 56 is provided with an enlarged shoulder portion 60 interiorly of the casing 58, and a compression spring 62 is mounted within the casing 58 to bear against the shoulder 60 so as to at all times urge the pin 56 toward locking engagement with the star wheel 55. v

The pin 56 is pivotally connected at its lower end by means of a connection device 64 to one end of a bell crank 65. The crank 65 is pivotally connected as at 66 to a stationary bracket 68, and carries at its opposite end a free running roller 10 arranged to engage the cartridge belt M in the manner of the engagement of the idler roller 26 of Fig. 1. Thus, it will be understood that upon imposition of drag forces upon the cartridge belt M by reason of operation of the gun feed pawl mechanism whenever the star wheel 55 is locked against rotation by the pin 56, the cartridge belt M will act upon the idler roller I0 so as to pivot the bell crank to pull the locking pin 56 out of engagement with the star wheel 55 against the action of the spring 62. Thus, the cartridge belt 14 will be freed for movement thereof toward the gun ID for normal feeding of the gun, but it will be understood that cessation of operation of the gun feed pawl mechanism or overrunning of the cartridge belt movement relative to the requirements thereof will automatically cause the belt to relax and allow the spring 62 to return the pin 56 to cartridge belt blocking position irrespective of the attitude of the aircraft mounting the gun and/or acceleration forces resulting from movements thereof.

Thus, it will be understood that the invention provides an improved mechanism of simple and rugged form which is adapted to automatically function to provide the features and advantages set forth hereinabove; and it will be understood that although only a limited number of forms of the invention have been shown and described in detail it will be apparent to those skilled in the art that the invention is not so limited but that various changes may be made therein without departing from the spirit of the invention or the scope of the appended claims.

I claim:

1. In combination, a machine gun having a cartridge feed mechanism, a cartridge belt magazine disposed above said machine gun, a cartridge belt partially nested within said magazine and having an end portion extending therefrom into operative connection with said gun feed mechanism, and a cartridge belt feed control accessory device disposed adjacent said magazine, said control device comprising a member geared to said cartridge belt for movement therewith; a stop finger member movably mounted and constructed and arranged to normally block said geared member, whereby said cartridge belt is held against movement out of said magazine and a crank connected at one of its ends with said finger member and bearing at its other end against said cartridge belt end portion to be actuated thereby upon tautening thereof to move said finger member to unblocking position, and means biasing said finger member to blocking position upon slackening of said cartridge belt.

2. In combination, a machine gun having a cartridge feed mechanism, a cartridge belt magazine disposed above said machine gun, a cartridge belt partially nested within said magazine and having an end portion extending therefrom into operative connection with said gun feed mechanism, a cartridge belt feed control accessory device disposed adjacent said magazine, said control device having a member geared to said cartridge belt for movement therewith and a stop device for blocking movement of said member, spring means normally urging said stop device to block said member against movement, motor means coupled to said member for moving the latter out of blocking position against the action of said spring means, cotnrol means for controlling the operation of said motor, and movable cam means engaging a portion of said cartridge belt at a position between said gun and said member and constructed and arranged to be moved by tautening of said cartridge belt portion, said cam means constructed and arranged during the movement thereof to engage and actuate said motor control means to operate said motor whereby said member and said cartridge belt are freed for movement by said stop device while the cartridge belt is tautened.

3. In combination, a machine gun having a cartridge feed mechanism, a cartridge belt magazine disposed above said machine gun, a cartridge belt partially nested within said magazine and having an end portion extending therefrom into operative connection with said gun feed mechanism, a cartridge belt feed control accessory device disposed adjacent said magazine, said control device having a member geared to said cartridge belt and a stop device normally blocking said member against movement, said stop devicebeing constructed and arranged to be moved out of blocking position relative to said member, electromagnet means for moving said stop device out of blocking position, control means for said electromagnetic means, and cam means movably mounted and normally bearing against said cartridge belt at a portion thereof between the positions of said machine gun and said stop member and so positioned to be moved in response to tautening of said cartridge belt portion, said cam means constructed and arranged to engage said control means during its movement by said belt portion, whereby said electromagnetic means is operated to free said stop device from its blocking position.

JOHN C. TRO'I'IER. 

